A document that purports to be signed or attested by a person who is authorized by a foreign country’s law to do so. The document must be accompanied by a final certification that certifies the genuineness of the signature and official position of the signer or attester — or of any foreign official whose certificate of genuineness relates to the signature or attestation or is in a chain of certificates of genuineness relating to the signature or attestation. The certification may be made by a secretary of a United States embassy or legation; by a consul general, vice consul, or consular agent of the United States; or by a diplomatic or consular official of the foreign country assigned or accredited to the United States. If all parties have been given a reasonable opportunity to investigate the document’s authenticity and accuracy, the court may, for good cause, either:

(A) order that it be treated as presumptively authentic without final certification; or

(B) allow it to be evidenced by an attested summary with or without final certification.

That's a lot of language, and the recent opinion of the Eleventh Circuit in United States v. McGowan, 2014 WL 184471 (11th Cir. 2014), does a good job of unpacking it.

In McGowan, Paul McGowan was charged with illegally re-entering the United States as a previously removed alien. At trial, the prosecution introduced into evidence an Application for Taxpayer Registration McGowan purportedly executed in Jamaica. There was no final certification accompanying the Application, but the court treated it as presumptively authentic pursuant to Rule 902(3).

After he was convicted, McGowan appealed, claiming, inter alia, that this evidentiary ruling was erroneous. The Eleventh Circuit disagreed, noting that "[t]here are three ways in which a foreign public document may be authenticated without additional extrinsic evidence under Rule 902." Specifically, the court pointed out that

First, a document may be formally "self-authenticating" under the primary paragraph of Rule 902(3), which requires a party to provide a final certification indicating that "the official vouching for the document [the signor or attestor] is who he purports to be."...Second, where a foreign public document lacks the proper final certification required under Rule 902(3)'s primary paragraph, subsection (A) of Rule 902(3) provides that the document may be "treated as presumptively authentic" if two conditions are satisfied: (1) the parties have been a “given a reasonable opportunity...to investigate the document's authenticity and accuracy”; and (2) "good cause" exists to excuse the missing final certification. Fed.R.Evid. 902(3)(A). Finally, subsection (B) allows a foreign public document "to be evidenced by an attested summary with or without final certification" upon the same showing of good cause and reasonable opportunity for inspection in subsection (A). Fed.R.Evid. 902(3)(B). "Good cause is a well established legal phrase[;][a]lthough difficult to define in absolute terms, it generally signifies a sound basis or legitimate need to take judicial action."

Applying this analysis to the case at hand, the Eleventh Circuit found that there was self-authentication under the second route, concluding that

First, McGowan had a reasonable opportunity to inspect the document. He received the document two weeks in advance of trial and never contacted the Government with any questions or doubts as to its authenticity during that time. He asserts that two weeks was insufficient for him to reasonably inspect the two-page Application, but he neither explains why he was unable to do so nor presents any evidence demonstrating the same.

Second, "good cause" excused the final certification requirement under Fed.R.Evid. 902(3). The uncontroverted evidence showed that the inadequate certification letter was due to the Jamaican government's delayed cooperation. That government provided the certification only three days prior to trial, despite the prosecution's diligence in requesting the document months earlier, and thus leaving the prosecution no time to obtain an additional certification before trial. Furthermore, the attaché officer ICE's Jamaica office, who personally obtained copies of the Application from the Jamaican police department, the custodian of the original document, testified to the document's authenticity. That testimony and the certification letter, even if insufficient to satisfy the final certification requirement under Rule 902(3), were nonetheless evidence of the Application's authenticity. McGowan failed to present any evidence undermining such authenticity. In sum, the record contains a "sound basis" underlying the court's ruling.